why are my Pro-form 545s treadmill consule display buttons locked? ?

This is a sudden problem; it came on quickly, and then came back on and worked perfectly for about a week. Now it is worse than ever--it powers up, but nothing works! The only button that makes a sound is the Stop button; all other buttons act like they are not being pushed--and they are not worn out. I tried the link for the online users manual but it is no longer active. The machine is in perfect condition except for this sudden issue. Not sure how to approach finding the problem....